The IAF would now have to submit a fresh proposal to the defence ministry, which will then issue another tender. This process is expected to take about a year.

The IAF has about 125 Jaguars, described as a deep penetration strike aircraft (DPSA). Given the evolving battlefield scenarios, the engine is regarded as underpowered to meet current requirements. A decision was taken a few years back to install more powerful engines to utilize the residual life of the airframe, and an RfP was issued on November 26, 2010.

The two companies were given time till April 22 to submit the RfPs.

But Rolls Royce recently withdrew from the competition, saying it had previously offered to upgrade the Adour-811 to the Adour-821 while the RfP was for re-engining. There was, however, no official word from the company.

The resultant single vendor situation forced the defence ministry to cancel the RfP, with the decision being communicated March 28.

The Adour-821 powers the Hawk advanced jet trainer ( AJT )), which both the IAF and the Indian Navy are already buying. Privately, Rolls Royce sources say that a single engine for the Jaguar and Hawk fleets would be cost-effective in maintenance terms.

Honeywell has countered that its engine is technically superior.

"Our F-125IN engine generates 30 percent more thrust than the competition, and we do hope that our technical superiority will be our winning edge," Pritam Bhavnani, president of Honeywell Aerospace India , said.

However, if the IAF chooses to go ahead with only one engine maker, then it will to go through the government concerned to either buy the engine in an FMS (foreign military sale)-type deal or on commercial terms from the company concerned.

Bhavnani said that Honeywell was supposed to give a demonstration to the IAF as part of the selection process after the RfPs were submitted. Although the RfP has been withdrawn, Honeywell is continuing work to fine-tune the engine for this demonstration as and when it takes place.

"We are ready when IAF is and we will prove the operational advantages of the F-125IN engine," he added. Honeywell has already tested the engine on an old Jaguar aircraft.

Significantly, Bhavnani also said that Honeywell was ready to share high levels of technologies with India, be they on aircraft or other systems.